forked from OSchip/llvm-project
3d85424096
https://maskray.me/blog/2022-01-16-archives-and-start-lib For every definition in an extracted archive member, we intern the symbol twice, once for the archive index entry, once for the .o symbol table after extraction. This is inefficient. Symbols in a --start-lib ObjFile/BitcodeFile are only interned once because the result is cached in symbols[i]. Just handle an archive using the --start-lib code path. We can therefore remove ArchiveFile and LazyArchive. For many projects, archive member extraction ratio is high and it is a net performance win. Linking a Release build of clang is 1.01x as fast. Note: --start-lib scans symbols in the same order that llvm-ar adds them to the index, so in the common case the semantics should be identical. If the archive symbol table was created in a different order, or is incomplete, this strategy may have different semantics. Such cases are considered user error. The `is neither ET_REL nor LLVM bitcode` error is changed to a warning. Previously an archive may have such members without a diagnostic. Using a warning prevents breakage. * For some tests, the diagnostics get improved where we did not consider the archive member name: `b.a:` => `b.a(b.o):`. * `no-obj.s`: the link is now allowed, matching GNU ld * `archive-no-index.s`: the `is neither ET_REL nor LLVM bitcode` diagnostic is demoted to a warning. * `incompatible.s`: even when an archive is unextracted, we may report an "incompatible with" error. --- I recently decreased sizeof(SymbolUnion) by 8 and decreased memory usage quite a bit, so retaining `symbols` for un-extracted archive members should not cause a memory usage problem. Reviewed By: peter.smith Differential Revision: https://reviews.llvm.org/D119074 |
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| .. | ||
| COFF | ||
| Common | ||
| ELF | ||
| MachO | ||
| MinGW | ||
| cmake/modules | ||
| docs | ||
| include/lld | ||
| test | ||
| tools/lld | ||
| utils | ||
| wasm | ||
| .clang-format | ||
| .clang-tidy | ||
| .gitignore | ||
| CMakeLists.txt | ||
| CODE_OWNERS.TXT | ||
| LICENSE.TXT | ||
| README.md | ||
README.md
LLVM Linker (lld)
This directory and its subdirectories contain source code for the LLVM Linker, a modular cross platform linker which is built as part of the LLVM compiler infrastructure project.
lld is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt.
Benchmarking
In order to make sure various developers can evaluate patches over the same tests, we create a collection of self contained programs.
It is hosted at https://s3-us-west-2.amazonaws.com/linker-tests/lld-speed-test.tar.xz
The current sha256 is 10eec685463d5a8bbf08d77f4ca96282161d396c65bd97dc99dbde644a31610f.